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Generators & Electric Motors General Discussion

Generac Stator Rewind? DPE Winding?


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  #1  
Old 10-10-2011, 10:34:42 AM
ProudDad2005 ProudDad2005 is offline
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Default Generac Stator Rewind? DPE Winding?

Gentlemen, I have a 20KW Generac diesel generator that had a shorted stator. I have found a motor shop that has rewound the stator but they failed to add the DPE winding and now I have no excitation at the voltage regulator. The motor shop claims they did not see a DPE winding when they disassembled the stator but after showing them the wiring diagram they conceaded that there was one. The motor shop says they can add the DPE winding if they know the wire size and the number of turns. I have tried to contact Generac and they refuse to talk to me. Is there any way to obtain this info? Can I use an aftermarket voltage regulator that does not need a DPE winding instead. Any help would be appreciated. Just paid a lot of money to rewind this stator and really hope it was not in vain. Unit model # is M99A02340-S. Serial # is 2047574.
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Old 10-10-2011, 10:42:20 AM
K D Redd K D Redd is offline
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Default Re: Generac Stator Rewind?? DPE Winding??

I would FIRST sue the rewind shop to get my money with damages back. If they can not tell the difference between a generator stator and a motor stator they DO NOT need to be in the rewinding business.

Kent
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Old 10-10-2011, 01:22:08 PM
Motorwinder Motorwinder is offline
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Default Re: Generac Stator Rewind?? DPE Winding??

I'd take it back and tell them to figure it out.

I have some old data that said 7 turns of #18.
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Old 10-10-2011, 03:19:29 PM
armandh armandh is offline
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Default Re: Generac Stator Rewind?? DPE Winding??

Ide just use a transformer rather than rewind
one with lots of windings can usually be bucked or boosted to the right voltage
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Old 10-10-2011, 04:11:15 PM
ProudDad2005 ProudDad2005 is offline
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Default Re: Generac Stator Rewind?? DPE Winding??

Mtorwinder, thanks for your help. That is more info then I can get from Generac. Do you think that old data is accurate for my 20KW?

---------- Post added at 03:11 PM ---------- Previous post was at 02:46 PM ----------

Armandh, what would you use for the primary input to the txfmr?
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Old 10-10-2011, 04:39:20 PM
Wayne 440 Wayne 440 is online now
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Default Re: Generac Stator Rewind?? DPE Winding??

The motor shop guys should be the ones calling/looking etc. for the DPE winding info, not you. You paid for a rewind, not part of a rewind.

One issue will be finding what voltage the Generac regulator requires from the DPE winding. A second will be how much residual voltage the set retains. It may require flashing on each start without the DPE winding.
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Old 10-10-2011, 06:18:04 PM
Arkie Arkie is offline
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Default Re: Generac Stator Rewind? DPE Winding?

Right on about it's the motor shop's issue now, even if they have your money already.

Take it back and dump it in their lap and do get a receipt for the return and get a expected turn around date. A good rewind shop can come up with that data! If you come up with the wrong data and give it too them, it's then your fault if their rewind don't fly!

Ask for the Supervisor/shop manager when you return and I would not even call, just go! If they start hum hawing and offer your money back take it, if they don't offer money back and their time limit runs out, go and tell them that Judy Judge is very interested in your case!
Try to get the name of someone with the company that has a email address and make later inquiries by email and keep their responses for court evidence for Judge Judy for later!
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Old 10-10-2011, 07:00:38 PM
Motorwinder Motorwinder is offline
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Default Re: Generac Stator Rewind?? DPE Winding??

Quote:
Originally Posted by ProudDad2005 View Post
Mtorwinder, thanks for your help. That is more info then I can get from Generac. Do you think that old data is accurate for my 20KW?

---------- Post added at 03:11 PM ---------- Previous post was at 02:46 PM ----------

Armandh, what would you use for the primary input to the txfmr?
This was for a 15KW Generac. http://www.poweredgenerators.com/gua...als/0E0226.pdfI'm betting the AVR is the same, so it be worth a try.

This one had a 12 pin plug. (show this to your winder)>>The 2 DPE coils in the stator had a 1- 10 span in the 24 slot stator. 2 adjacent coils, all leads brought out for a total of 6 leads. One at start, one tapped to the 4th turn, one at finish. on both coils. One #18 7 turns. Of course the leads hook to the plug, and I'd have to scan my data sheet to show how it hooked. But this should give them the basic info for the coils and taps. I'll try to explain though. With plug tab facing down, number the pins 1-12. Start of 1st coil is pin #2. Tap of 1st coil is pin #4. Finish of 1st coil is pin#3. Start of 2nd coil is pin #10. Tap of 2nd coil is pin #8. Finish of 2nd coil is pin #9.

Hope this helps. Good luck.

---------- Post added at 04:00 PM ---------- Previous post was at 03:40 PM ----------

Quote:
Originally Posted by Arkie View Post
Right on about it's the motor shop's issue now, even if they have your money already.

Take it back and dump it in their lap and do get a receipt for the return and get a expected turn around date. A good rewind shop can come up with that data! If you come up with the wrong data and give it too them, it's then your fault if their rewind don't fly!

Ask for the Supervisor/shop manager when you return and I would not even call, just go! If they start hum hawing and offer your money back take it, if they don't offer money back and their time limit runs out, go and tell them that Judy Judge is very interested in your case!
Try to get the name of someone with the company that has a email address and make later inquiries by email and keep their responses for court evidence for Judge Judy for later!

Getting the data would be a major problem for the motor shop. Proprietary information they won't cut loose with. If they can't get it to work, the only thing the motor shop could do is buy him a new stator.
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Old 10-10-2011, 08:29:07 PM
Lloyd H Lloyd H is offline
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Default Re: Generac Stator Rewind? DPE Winding?

If the rotor resistance is high enough for a SX-460 (min of 15 Ohms I think) the rewind shop might spring for it and make you an AVR genset out of it.
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Old 10-10-2011, 10:24:30 PM
Motorwinder Motorwinder is offline
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Default Re: Generac Stator Rewind? DPE Winding?

You could put a Bassler SR1 on it, if you can tap 115 volts.
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Old 10-10-2011, 10:56:16 PM
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Default Re: Generac Stator Rewind? DPE Winding?

Yes,

It is very likely you can run this unit without the DPE winding/third-party regulator. Its a dedicated source for the Generac voltage regulator. I've converted Generac's to other regulators--you'll just have to find one that is tolerant to the field ohms, as Generac loved their low-ohms fields.

(i believe the spec for the Onan 200-2880 you hear mentioned on this board is a very low ohm field tolerant unit--but I can find the info i was looking for tonight. You might want to call Flight Systems and see what they say about their spec's for their replacement unit for the 300-2880.)

eric
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Old 10-11-2011, 09:36:47 AM
ProudDad2005 ProudDad2005 is offline
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Default Re: Generac Stator Rewind?? DPE Winding??

Wayne 440, you made a comment that it will need to be flashed everytime without a DPE winding. I did attempt to flash the field with 12vdc and the voltage only raised to 158vac L to L. When I removed the 12vdc the voltage dropped to 80vac L to L. Is this normal since the DPE winding is missing or should that have reached 240vac L to L even without the DPE winding? Do you think there is another problem with the stator. The owner of the rewind shop personally inspected the stator and said that there was nothing wrong with the rest of it but what I dont understand is that shouldnt have I been able to get correct L to L voltage when applying 12vdc directly to the brushes?

Just to give a little more history on this generator. its a 20kw and before I took the stator in to the rewind shop the unit produce steady 120/240vac. The problem was is that it started sounding like there were loose rocks or marbles in the generator end. After inspection during operation I found a lot of arcing and sparking going on between the rotor and stator. Also the stator was getting extremely hot in one spot. Hot enough I was unable to hold my hand on it. The rewind shop said one of the coils in the stator was shorting to ground. They rewound the stator and ever since have had the issue above.
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Old 10-11-2011, 10:31:13 AM
Gunny Gunny is offline
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Default Re: Generac Stator Rewind? DPE Winding?

How about this?

Involve the rewind shop as they have a huge interest in this.

Go here: http://www.power-tronics.com/ They have a regulator that will work for about any generator ever made.

Feel it should be the rewind shops responsibility to make this right.
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Old 10-11-2011, 10:32:11 AM
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Default Re: Generac Stator Rewind?? DPE Winding??

This is very difficult to diagnose long distance. I will tell you about a recent experience that may help, as you may have a similar issue.
Gen was rewound, would not produce full voltage. Returned to shop, who said it was rewound correctly. Owners took it to a generator specialty shop, which blew a diode in the bridge, but could not find a problem.
I was asked to look at it. I replaced the diode. After lot of tests, I concluded one of the coils was hooked up backwards! I wrote instructions on how to reconnect coil, they took it back to original shop, he said that would be backwards, and coil would burn out. They reconnected it. Generator now produces normal voltage and full rated kw.
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Old 10-11-2011, 10:36:31 AM
armandh armandh is offline
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Default Re: Generac Stator Rewind?? DPE Winding??

Quote:
Originally Posted by ProudDad2005 View Post
[/COLOR]Armandh, what would you use for the primary input to the txfmr?
I'm looking at a 17.5 KW generac sheet and it looks as if the DPE winding supplies just the voltage regulator through a circuit breaker. I presume it is the field power as the regulator and speed governor get voltage reference from two separate leads attached to the main output windings

so on second thought an after market regulator such as
http://www.partsfortechs.com/asapcar...648-p-153.html
would do the job better if you cant get the rewind free

I would use a variac and an isolation transformer to determine the needed voltage from the mains.
by bringing up the ac power feeding the VR to the point of proper output and then noting the steady output raise it a few volts more.

then watch it under varying load
the isolation is needed because of generac's use of a continuous flashing,
and the few volts more to provide the head room for power input voltage fluctuation under changing main output load

Last edited by armandh; 10-12-2011 at 07:24:50 AM.
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Old 10-11-2011, 03:04:59 PM
ProudDad2005 ProudDad2005 is offline
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Default Re: Generac Stator Rewind? DPE Winding?

Someone help me out, the part that I am question is if the stator has been wound wrong. Taking the voltage regulator and DPE winding out of the equation shouldnt I still get full L to L voltage when I placed 12vdc directly to the brushes?
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Old 10-11-2011, 03:10:31 PM
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Talking Re: Generac Stator Rewind? DPE Winding?

That would depend on the design of the Genend. Was it designed for a nominal 12Vdc Exciter Voltage to produce 120/240Vac, or maybe 18Vdc, or maybe 24Vdc? Unless you know what the Genend Exciter Voltage should be, for Nominal Output AC voltage, you can't answer that question.
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Old 10-11-2011, 03:16:26 PM
ProudDad2005 ProudDad2005 is offline
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Default Re: Generac Stator Rewind? DPE Winding?

Wouldnt that be decided by the voltage regulator. Generac part #67680.
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Old 10-11-2011, 04:37:10 PM
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Default Re: Generac Stator Rewind? DPE Winding?

Quote:
Originally Posted by ProudDad2005 View Post
Someone help me out, the part that I am question is if the stator has been wound wrong. Taking the voltage regulator and DPE winding out of the equation shouldnt I still get full L to L voltage when I placed 12vdc directly to the brushes?
that is the typical test to check for a functioning gen end. but not necessarily the correct voltage.

the transformer idea is ok if you have one around but otherwise the aftermarket VR is the easiest to do.
I have not seen any spec on my print for excitation voltage.

but it looks as if the reference voltage causes the regulator to vary the output created from the DPE winding source.


having no idea about the VR innards I suggested a test with a variac. but measurements from a working unit would be easier


a constant voltage to the field would give varying output voltage with varying load
voltage regulators keep the output voltage constant by varying the field voltage/current to compensate for varying load.

Last edited by armandh; 10-12-2011 at 08:05:07 AM.
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Old 10-11-2011, 06:38:14 PM
Wayne 440 Wayne 440 is online now
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Default Re: Generac Stator Rewind?? DPE Winding??

Quote:
Originally Posted by ProudDad2005 View Post
Wayne 440, you made a comment that it will need to be flashed everytime without a DPE winding...
I stated that it "may require flashing"- that largely depends on how much residual voltage the unit retains.

Quote:
Originally Posted by ProudDad2005 View Post
...flash the field with 12vdc and the voltage only raised to 158vac L to L. When I removed the 12vdc the voltage dropped to 80vac L to L. Is this normal since the DPE winding is missing or should that have reached 240vac L to L even without the DPE winding? Do you think there is another problem with the stator...
It is making voltage, that is a good sign. As others indicate, the excitation voltage may have to be more that 12V for full output. There could or could not be "another problem" with the stator.

Quote:
Originally Posted by ProudDad2005 View Post
...The owner of the rewind shop personally inspected the stator and said that there was nothing wrong with the rest of it...
My confidence in the rewind shop would not be absolute, as they somehow managed to leave an entire winding out of the job.
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